I configure 3750 stack switch as core and 2960 stack switches as access layer switches.I connected my laptop to one of my core stack in VLAN 10 and I am pinging to one of my server in VLAN 1. What will be the minimum latency at the time of inter VALN routing

I've been fighting what seems to be an increased number of outqueue drops on our core stack and edge switches for the last 3 or 4 weeks.(The core consists of a stack of 5 3750s in 32-gig stack mode. The wkgrp switches are 3560s. all are at 12.2.52) The wkgrp switches are directly connected to users. We use Nortel IP phones with the phone inline with the user PC. auto-neg to 100/full. [code] However I have tried turning off QOS on a couple of workgroup switches (no mls qos, but left individual port configurations the same) but am still seeing drops.Since I have disabled qos on the switches in question (no mls qos) (not the core tho) I am presuming these commands have no affect on the switch operation and therefore cannot be related to the problem. With QOS turned off one would presume that it is general congestion - especially at the user edge where busy PC issues might contribute. So I wanted to see if I could see any instances of packets in the output queues building up.

I wrote some scripts and macros that essentially did a snapshot of 'show int' every 20 seconds or so, and looked for instances of 'Queue: x/' where x was greater than zero.What I found after several days of watching the core stack, and a few of the workgroup switches that are most often displaying the behavior, was that I NEVER saw ANY packets in output queues. I often saw packets in Input queues for VLAN1, once in a great while I would see packets on input queues for fa or Gi interfaces, but NEVER on output queues. [ code] Additionally, when I look (via snmp) at interface utilization on interfaces showing queue drops (both core and wkgroup), they are occurring at ridiculously low utilization levels (as low as 4 to 8%). I've tried to look for microbursts between the core and a wkgroup switch where the core interface was experiencing drops, but haven't seen any (using observer suite). [code] While the queue-drop counts aren't critically high at this point, they are happening more frequently than in the past and I would like to understand what is going on... In most cases, no error counters are incrementing for these interfaces. Is there some mechanism besides congestion that could cause output queue drops?

So my question is in Core / Distribution layer should i use Etherchannel between switches or use Stacking if switches are stackble.For ex: suppose I have two cisco 3750 switches . so should i use etherchannel between them or use stacking in core layer?What are the advantages and disadv of both.

I have an existing stack of 4 x 2960-S switches connected by stack cables.I would like to add another 2960-S switch to the stack but am unable to as the 2960-S will only allow 4 x 2960-S switches per stack.how I would add the 5th 2960-S switch to the existing stack of 4 x 2960-S switches.

If I have two stackable switches one switch uplinks to one 6509 core switch and the other connection uplinks to another 6509 core switch, and also the other stackable switch does not connect to the core switches. Because I am using hsrp and also we are not using vss then one uplink to the core is not in used only ones is so then how does creating an etherchannel between does two uplinks to both core switches benefit me in anyway such as more bandwith and using both uplinks at the same time or I'm I wrong?

If I have two stackable switches were only one stackable switch has two uplinks one uplink goes to one core 6509 switch and the other uplink goes to the other 6509 core switch can a Layer 3 etherchannel be used if each uplink go to a different core switch, by the way hsrp is running between both switches and also can you give an example how data will be routed from the stackable switch through the ethernetchannel to one of the core switch accross the WAN to another core switch?

We have a pair of WS-C3750X-24T-S in a stack and four WS-C2960S-48TS-L in a stack of their own. There is not really anything too fancy configured (no special VLAN configuration/trunks or etc.) but the 3750 do have two ports configured as L3 for routing. We are not trying to use those ports for EtherChannel. These devices are running IOS 12.2(55)SE3 Essentially we are attempting to make an EtherChannel group using port 48 on all four of the 2960's in their stack (four ports). On the 3750 we will configure an EtherChannel group using port 23 and 24 on both switches (four ports). We then connect them up to form a four member EtherChannel.The ports on both ends are configured as mode ON and they are all 1Gb ports. I elected mode on because I understand at least one of the EtherChannel protocols will not work cross stack. What I would like to ask is whether the above configuration is possible or are we hitting some sort of limitation of EtherChannel cross stack, etc..? I cannot find anything to suggest this configration is invalid, but thought I would ask to see if I missed something in the EtherChannel articles.

This is probably a dumb question, but I have read the 2960 stack administration guide and it does not explain how to configure the stack IP address. It says several times that the stack can be managed from the stack IP address, and that the stack IP address is a system-level configuration item. But it never explains how to configure the stack IP address.

The company I work have finally decided to enter the 21st century and invest in a new telephone system (Interactive Intelligence) to replace the legacy system which has served us well for the past 10 years. The project has only just started and involves upgrading sections of CAT3 cabling to CAT6, replacing Cisco 3550 switches in one area of the building with Cisco 4507 switches and upgrading our Core switches with Cisco Nexus 7010's. The area that concerns me most is enabling the network for qos as I have very little experience with it. At the moment Im trying to read as much documentation as I can on QOS to bring myself up to speed.

The access layer switches will consist of a mixture of Cisco 3750 & 4507 switches connected to Cisco Nexus 7010 switches which will form a collapsed aggregation & core layer.

Basically, how I should approach this daunting task of making sure the network will support VOIP.

Looking for feedback from other organizations that have large 3750 stacks. I've got one stack of (8) 3750's composed of (6) 3750G's and (2) plain 3750's. This particular stack is usually unresponsive to SNMP queries and often fails to write config when we make changes. After a couple tries it will finally go. Part of my probably here is likely the plain 3750's that always boot faster and come up as the master. I should manually set the master to one of the G's. What I'm wondering is who else has 7-9 3750's stacked and are they performing well for SNMP, telnet, etc? I've got another newer stack of 7 3750E's that I need to add one more switch to. Need to decide if I want extended downtime to break the stack up or just add the 3750X to make member 8 and hope it performs well. I have 50+ 3750 stacks working great on our campus.

I am trying to do ios upgrade on 5 stacked 3750 switches. All the switches have different model number, so i am wondering which image file i should download. As far as i understand all the stacked switches should have the same IOS, i may be wrong. The switches have the following model numbers and SW images;

I am wanting to etherchannel from a 3750 stack to core Layer 3 switches (also 3750) with a cable going to each core switch, I have put both core switches and the stack under a 28bit subnet mask, but I dont seem to be load balancing across both links.

The new switch is installed to be wired to the master switch. the swtich 3 (* 3 Master Ready 442b.036f.a800)my question is: if you disconnect the wiring from the master stack to connect to the new switch, it is possible that the new switch change the current configuration of stacking.

-Can I just add the new switch with clean configuration without changing the current configuration ?-How is assigned the stack number? i need the new switch be with the GI4 / x?. I can I manually by assigning ports?-If I want to the new 3750 member witch lower prioridad, can I change priority before adding to stack?

I have a question for Cisco Cat.2960-s Flex Stack switches which are installing on our sties. Two of 2960-s Stack switches as access switch and two of Cisco ME 3600X Series as distribution layer switches are to be installed in our sites. In case of two stack switches, One is will be a Master and the other one will be a member logically, as you know. So, if the master fails, the other one automatically becomes the stack master following a well-documented election process.

Now, it is my question. How long takes to be a stack master from a member switch ? I cant find it on white paper of Cat.2960-s flex stack .And also, I heard that sometimes a member switches don't election process when the master fails as a result, all stack members becomea panic. Is that really right ? In addition, I heard that the stack switches have many troubleshooting points than stand alone switches.I really wanna know if the stack switches are good solution for resilience of huge network site. I'm waiting an answer from those who have experience of maintenance or installation.

Lets say i have 2 3750 switches stacked via backend stack cables. Now if a packet needs to go from 1 switch in the stack to second switch in the stack, will it travel via stack cable or do we need to connect both switches via uplink ports (ethernet or sfp). I tried reading datasheet but it no wheres mention the actual frame path between switches in stack.

I'm thinking about using a 3750 stacking around 4 or 5 switches intead of using one 4500 series switch.

1-My first argument was concerning the budget (one 4500 instead of four or five 3750 in stack mode) ---- Here i think 4 or 5 stacked 3750 is cheap than one 4500 2- My second argument was about harware redundancing that i don't have with one 4500 and that i have with stack mode ----Here i have more hardware redundancing with 3750 3- The bug that we notice today in 2960 and 3750 and not in 4500 4- Simple to manage a 4500 compare to 3750 stack design 5- I was looking also for the one with best backplane ----Here i didn't have any infos concerning the best backplane between 4 or 5 stack 3750 and a 4500. 6- I'm also looking for power redundancing.

I have an issue with a Cisco 3750 switch stack which is connected to two seperate upstream Cisco 3750's which are administered by an ISP. The ISP is experiencing MAC address flapping from one of my VLAN SVI's i am using to route traffic upstream

[code]...

As you can see I utilise a VLAN SVI to route traffic to the upstream 1.1.1.2 (illustration only) IP. As per the diagram of the topology attached, the ISP is receiving a MAC address flapping error confirming the SVI MAC address from my switch stack is being learnt on the trunk port connecting switch 1 and switch 2, and also the port (Gi1/0/48) directly connected to my switch stack. As these are all Layer 2 links essentially being passed upstream and then connected between the two ISP switches, we have a 3 way triangular loop formed.

If I was to remove the port channel configuration from the two ports associated with the VLAN SVI, am i right in suggesting this would still form a layer 2 loop? The two ports would still be a member of the SVI VLAN, and it is the VLAN MAC address which is being learnt by the two ISP switches on different interfaces.

I've got a bunch of 3750-X switches all running IP Base and acting as a routed access layer. They run OSPF in a totally stubby area with the distribution layer (Nexus 7K) as the ABR. We also have a physically separate management network into which the fa0 management interface of the 3750-X is connected. The management network itself runs OSPF and has multiple subnets and external access.

On the 3750-X, I'd ideally like to be able to run some sort of separate OSPF process for the management network or at the very least have a static default route for management traffic pointing out the fa0 interface, but clearly not have it interfere with the main default route for data traffic coming from the N7K ABR. Normally I'd just create a management VRF, sling the fa0 interface into it and run a separate OSPF process in that VRF. The problem is you can't create VRFs in IP Base! Surely there must be a way to do this? Cisco don't really expect customers to upgrade to IP Services just to have a working OOB Management network, do they?!

My colleague and I have been having a discussion about using rapid spanning tree in the access layer. Most of our infrastructure has been migrated to a routed access layer with 3750s.

The idea was brought up to configure the switches with rapid PVST. On the surface, it seems like a better idea, faster convergence, in the event that spanning tree ends up being used for some reason. My colleague prefers sticking with standard PVST. His argument is that, in the event of a layer 2 loop, some consumer-level switches filter out BPDUs and if the control plane is overwhelmed, the shorter timers of rapid PVST just puts that much more of a burden on the CPU trying to regain control, whereas with standard PVST it will have around 20 seconds before it starts to engage. (It may still be overwhelmed, but the longer timer delays the additional burden.) He says he's seen this problem with rapid PVST and that his opinion is backed up by our Cisco rep. (I haven't spoken to him yet.)

In our model, it should be very rare -- pretty much never -- that we would layer 2 span another switch off of our access stack.

One suggestion I saw is to use BPDU Guard, which is a good suggestion as well.

But we have had experiences with overloading the control plane on a 3750. I believe that concern is valid. If the CPU can't service spanning tree. But I'm interested in hearing about other experiences people have had in terms of rapid spanning tree in the access layer, end users plugging in unauthorized devices and creating loops, and the effects when using rapid spanning tree vs standard spanning tree.

I am using a 3750 as a default gateway for multiple Vlans on a few 2960 switches. The trunk lines are configured and working and I have assigned ip addresses to each of the Vlan interfaces on the 3750. My issue is that I can only ping the ip address on the Vlan interface of the 3750 if I have a working computer plugged directly into the Vlan on the 3750. I only have 3 vlans on the 3750 that have hosts directly connected (vlans 2, 10 and 40) the other vlans ( 20 and 70) don't have any clients plugged into them on the 3750 but the hosts reside on 2 different 2960s that connect via trunk ports. How do I keep the vlan interface on the 3750 switch pingable when I don't have hosts directly connected in that vlan on the 3750? (yes, I have enabled ip routing on the 3750)

We have a Cisco 3750G Core switch which has physical connections, each configured as trunks to two HP Access switches. The client who uses these access switches would like to put a link between the two, but this would create a loop.

We have got 2 3750 switches in the stack which are connected to access switches with 2 uplink ports . each 1 uplink from each physical stack switch .

Due to some power issue our member switch got rebooted. After the reboot the access switches were not reachable through ping , but i was abe to see access switches in "show cdp neighbour" . Then i rebooted the master switch and member switch one after other . after which i was able to ping the access switches.

3750 switch connects to Blade-switch_1 and Blade-switch_2 Spanning-tree mode is configured as rapid-pvst on 3750 switch, do I need to configure rapid-pvst on both blade-switches or keep the default pvst config.3750 is running VTP domain HQ and transparent mode Both Blade_switches are running VTP domain CLI and transparent mode To configure Etherchannel between 3750 and blade-switch_1 do I need to have all devices in same vtp domain?

I've been taught/under the impression that vlans and stp stay in the access layer to prevent bridging loops and broadcast storms from taking down the whole network. Well I was reading about backbonefast and how it "Enables fast convergence in the networkbackbone or core layer switches after a spanning-tree topology change occurs." Now I thought that from the distribution layer up we use a routing protocol.

choosing a core switch, to replace a swich 3com model 4924, its main function is to support a 4-LAN switch cisco 2960 (100 users) and a ring cluster of 12 servers.obs. Current 3com core switch has 56 Gbps performance and 41.6 million packets per second.

I can understand it 's one of those very basic questions , but how do I identify a Switch is Layer 2 or Layer 3 ?Looking through # show version command and checking the IOS version to be IP BASE or LAN BASE . Is it the right way ?Cisco 2960 is a Layer 2 or a Layer 3 Switch ? I noticed that access-lists could be configured which means that it 's a Layer 3 Switch , right?